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Fencer Vulns
critical 9.1

CVE-2026-7598 json

libssh2 userauth.c userauth_password integer overflow

published 2026-05-01 6 mo ago modified 2026-09-01 2 mo ago also EUVD-2026-26722 , JLSEC-2026-492

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

A security vulnerability has been detected in libssh2 up to 1.11.1. The impacted element is the function userauth_password of the file src/userauth.c. Such manipulation of the argument username_len/password_len leads to integer overflow. The attack may be launched remotely. The name of the patch is 256d04b60d80bf1190e96b0ad1e91b2174d744b1. A patch should be applied to remediate this issue.

Patch / fix

  • julia LibSSH2_jll 1.11.101+0
  • Red Hat Red Hat Hardened Images 1.11.1-5.1.hum1, 1.95.0-5.hum1
  • libssh2 Debian 12 1.10.0-3+deb12u1
  • libssh2 Debian 13 1.11.1-1+deb13u1
  • libssh2 Debian 14 1.11.1-3

debian advisories DEBIAN-CVE-2026-7598

  • libssh2 Ubuntu 24.04 LTS 1.11.0-4.1ubuntu0.24.04.1
  • libssh2 Ubuntu 25.10 1.11.1-1ubuntu0.25.10.1
  • libssh2 Ubuntu 26.04 LTS 1.11.1-1ubuntu0.26.04.1

ubuntu advisories UBUNTU-CVE-2026-7598

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rust hummingbird 1 1.95.0-5.hum1
  • rustfmt hummingbird 1 1.95.0-5.hum1
  • rust-gdb hummingbird 1 1.95.0-5.hum1
  • rust-src hummingbird 1 1.95.0-5.hum1
  • rust-lldb hummingbird 1 1.95.0-5.hum1
  • rust-analyzer hummingbird 1 1.95.0-5.hum1
  • rust-debugger-common hummingbird 1 1.95.0-5.hum1
  • rust-std-static-wasm32-wasip1 hummingbird 1 1.95.0-5.hum1

red hat advisories RHSA-2026:61752RHSA-2026:16736RHSA-2026:7021

  • libssh2_org SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 1.11.0-150000.4.35.1
  • libssh2_org Linux Micro 6.0 1.11.0-4.1
  • libssh2_org Linux Micro 6.1 1.11.0-slfo.1.1_2.1
  • libssh2_org SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.11.1-160000.5.1
  • libssh2_org SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 1.11.0-150600.20.6.1
  • libssh2_org SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 1.11.0-150200.9.8.1
  • libssh2_org SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 1.11.0-29.18.1

suse advisories SUSE-SU-2026:4095-1SUSE-SU-2026:23245-1SUSE-SU-2026:23187-1SUSE-SU-2026:23049-1SUSE-SU-2026:23214-1SUSE-SU-2026:23225-1

  • libssh2_org openSUSE Leap 16.0 1.11.1-160000.5.1
  • libssh2_org openSUSE Tumbleweed 1.11.1-3.1

opensuse advisories openSUSE-SU-2026:21549-1openSUSE-SU-2026:11109-1

  • libssh2 Alpine 3.20 1.11.0-r3
  • libssh2 Alpine 3.22, Alpine 3.21 1.11.1-r1
  • libssh2 Alpine 3.24, Alpine 3.23 1.11.1-r2

alpine advisories ALPINE-CVE-2026-7598

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh2 Azure Linux 3.0 1.11.1-2
  • rust Azure Linux 3.0 1.75.0-30
  • rust Azure Linux 3.0 1.96.1-2

azure linux advisories AZL-85451AZL-97404AZL-97431

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-7598 updated cvss 9.1

libssh2: integer overflow via large username or password arguments

  • Red Hat Enterprise Linux 6 libssh2
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux Server (v. 7 ELS) libssh2 1.8.0-4.el7_9.2 Red Hat Enterprise Linux Server Optional (v. 7 ELS) libssh2-devel 1.8.0-4.el7_9.2
    fixed: vendor fix RHSA-2026:61752
  • Red Hat Hardened Images rust 1.95.0-5.hum1, rustfmt 1.95.0-5.hum1, rust-gdb 1.95.0-5.hum1, rust-src 1.95.0-5.hum1, libssh2 1.11.1-5.1.hum1, rust-lldb 1.95.0-5.hum1, +10 more
    fixed: vendor fix RHSA-2026:7021
  • Red Hat Enterprise Linux Server (v. 7 ELS) libssh2-debuginfo 1.8.0-4.el7_9.2 Red Hat Enterprise Linux Server Optional (v. 7 ELS) libssh2-docs 1.8.0-4.el7_9.2, libssh2-debuginfo 1.8.0-4.el7_9.2 Red Hat Hardened Images cargo 1.95.0-5.hum1, clippy 1.95.0-5.hum1
    not affected: vulnerable code not present
  • Red Hat OpenShift Container Platform 4 conmon-rs
    not affected: component not present
  • Red Hat OpenShift Update Service openshift-update-service/openshift-update-service-rhel8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • vuldb.com https://vuldb.com/submit/805564 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA 3.0 7.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:O/RC:C
CNA 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P/E:ND/RL:OF/RC:C
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
OSV 3.1 7.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
julia LibSSH2_jll
<1.11.101+0
1.11.101+0

Affected products

  • n/a libssh2
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Update Service
  • Red Hat Red Hat Trusted Profile Analyzer

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.